1. Field of the Invention
The present invention relates to waveguide junctions and particularly to a three-port junction in which one of the ports will accept energy in two orthogonally related directions of polarization and the other two ports are E- and H-arm ports.
2. Description of the Prior Art
Past three-port junctions in which one port accepts two orthogonally related modes have been commonly designed for operation over a narrow frequency range. For example, the present junction was obtained in designing a junction for use between 5,200 and 5,800 MHz. Beyond a design frequency band with a frequency ratio of about 1.1 to 1, voltage standing waves commonly produced by junctions of this type become excessively high.
A voltage standing wave ratio over 1.5 is normally considered unacceptable and waveguide will normally propagate energy with acceptable efficiency over a frequency band having a ratio of about 1.5. Thus, in order to use the same waveguide junction over the whole useful frequency range of a particular waveguide, the junction desirably introduces less than a 1.5 VSWR over a frequency ratio of 1.5 to 1.